A tire is a composite of several components each serving a specific and unique function yet all synergistically functioning to produce the desired performance. One important component is the carcass ply. The carcass ply is a continuous layer of rubber-coated parallel cords which extends from bead to bead and functions as a reinforcing element of the tire. The ply is turned-up around the bead, thereby locking the bead into the assembly or carcass. In the immediate proximity of the carcass ply turn-up is an apex. The apex includes a rubber wedge located in the lower sidewall region above the bead and is bonded to and encased by the carcass plies. The apex also includes the area located between the lower sidewall rubber and the axially outer side of the carcass ply turn-up. Between the bead and apex, a flipper may be included, and between the carcass ply and chafer, a chipper may be included. The apex serves to stiffen the area near the bead in the lower sidewall. The flipper serves as an interface between the bead and carcass ply, to prevent erosion of the carcass ply and/or bead due to interfacial stresses. The chipper serves as an interface between the carcass ply and the rubber chafer contacting the wheel rim.
The apex, flipper and chipper performance may improve when reinforced with short fibers having a specific orientation. For example, an apex with radially oriented fibers may improve the bending stiffness of the lower sidewall of the tire. Known techniques for orienting reinforcing short fibers in an elastomeric material are generally methods for orienting fibers in a composite in a direction which is consistent with and parallel to the material flow direction in processing equipment. However, such fiber orientation is often difficult to achieve in practice due to poor dispersion and/or adhesion of the fibers to the rubber. There is, therefore, a need for an improved apex, flipper, or chipper with oriented short fibers.